Ukraine's President Petro Poroshenko, center, poses with European Commission President Jose Manuel Barroso, left, and European Council President Herman Van Rompuy, right, during an EU Summit in Brussels on Friday, June 27, 2014. Ukrainian President Petro Poroshenko has signed up to a trade and economic pact with the European Union, saying it may be the "most important day" for his country since it became independent from the Soviet Union. (AP Photo)